chapter 3 Flashcards
(122 cards)
1
Q
cell type of nervous system
A
neurons and glia
2
Q
Neuron
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Responsible for communication; transmit, receive and integrate information
3
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glia
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support, nourish and protect cells, *they can be replaced unlike neurons
4
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3 main parts of the neuron
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dendrites, cell body or soma, axon
5
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dendrite
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branching region of neurons
6
Q
cell body or soma
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contains the nucleus, genetic blueprint that guides the cells functions or producing proteins and chemical messages
7
Q
axon
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“root” how it passes through (how its transmitted), moves along the axon, chemicals release at the end of the axon so the other cells get the message, covering the axon is a type of glia cell
8
Q
Myelin Sheath
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insulates axons and speeds transmission of signals, they are white, it is why we say “white matter” just glia cells , information and messages passed much quicker with the myeline sheath
9
Q
multiple sclerosis
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de-myelinating disease. auto immune disorders that attack the myeline sheath, problems with muscular movement, tend to come and go
10
Q
hodgkin and huxley
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1952, first ones to explain nerve impulse, won the nobel prize
11
Q
hodgkin and huxley experiment
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take squids (have large axons) can embed an electrode inside the neuron and outside to see what electro pulses are going on. fluid inside and outside the cell within the fluid there are electrically charged ions
12
Q
resting potential
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stable negative charge -70mV
13
Q
neuron at rest
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negative charge on inside compared to outside of cell
14
Q
ions involved neural impulse
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potassium (k+) inside of the cell, sodium (Na+) on the outside
15
Q
Action Potential cause
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spike caused by a change in the flow of the ions
16
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action potential ion flow
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little gates or channel all along the axon open when stimulated to create a change in ion concentration, Na rushed in, once it moves past K goes out, resetting the resting potential
17
Q
What happens when the action potential moves along the axon
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it reaches the terminal buttons which release neurotransmitters
18
Q
threshold for action potential
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-50 mV
19
Q
Depolarization
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Na+ ions rush into the cell making the inside of the cell positive
20
Q
Repolarization
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K+ ions rush out of the cell, resetting the charge making it negative
21
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Hyperpolarization
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during the time that so many k+ ions rush out of the cell it becomes more negative than the resting period, then the gates close and the concentration returns to resting potential
22
Q
transmit action potential to other cells
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the ion flow at one location creates a charge that affects the neighbouring regions that spark the action potential of the next region…
23
Q
Speed of action potential
A
1 millisecond (100m/s)
24
Q
Relative refractory Period
A
where you could create a new action potential but the cell needs more stimulation, during hyperpolarization. Extra work to generate another action potential, threshold is bigger because the cell is so negative, so you would need a lot of excitatory stimulation
25
Absolute Refractory period
depolarization refers to the fact that you cannot generate another action potential in the cell, no matter how strong the stimulus another action potential will not occur
26
all or none law
refers to the fact that if we get to the -50mV we will have an action potential if we dont we will get nothing
27
Characteristics of every action potential
same magnitude, same overall change is electrical energy were recording over the membrane, variable firing rate, travels extremely fast
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Variable Firing Rate
different cells will fire action potential at different rates (how many times a second does this happen in a cell)
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travels extremely fast
a myelin sheath allow for the information to move that fast 100m/sec, produce action potentials to code for different information. we need motor and sensory information to travel really quickly so that our body responds to prevent injury
30
Where are neurotransmitters stored
synaptic vesicles
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Where are neurotransmitters released
into the synaptic cleft and binds to receptor sites, after action potential
32
Post-synaptic potential
neurotransmitter produces a change in voltage at receptor site--> Excitatory, inhibitory, not all or none, can have a small effect, doesn't spread across the cell. NOT the same as action potential
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Excitatory Post-Synaptic Potential (ESPS)
depolarizing effect, brings us closer to an action potential, if enough will cause an action potential
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Inhibitory Post-Synaptic Potential (ISPS)
(hyper)polarizing effect, brings us further away from an action potential
35
Removal of neurotransmitter from the synapse
need to inactivate the neurotransmitter once its in the synaptic cleft; enzymes that will break down the neurotransmitter so it cant bind to the receptors on the post synaptic cell, take it back into the terminal buttoms and repackage them known as reuptake, because we want to retain that neurotransmitter
36
flow of neurotransmitters
1. synthesis and storage of neurotransmitter molecule in synaptic vesicles
2. Release of neurotransmitter molecules into synaptic cleft
3. Binding of neurotransmitters at receptor sites on postsynaptic membrane
4. Inactivation by enzyme or removal by drifting away
5. Reuptake of neurotransmitters by the presynaptic neuron
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Connection between neurons
pre-synaptic and the post-synaptic cells
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long term potentiation (LTP)
once the cell has been stimulated there can be prolonged period of time when the connection is strengthened for hours, days, etc.
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Pruning
refers the process by which excess neurons and synaptic connections are eliminated to increase efficiency of neuro transmissions
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different classes of neurotransmitters
small molecule: developed and synthesizes using amino acids, fast acting, developed from our diet
Neuropeptide: protein developed by the cell that are synthesized and can be used as neurotransmitters
other: behave very differently, some that are gases, when neurotransmitters are needed they move along the cell
50 neurotransmitters
hard to figure out if a chemical is a neurotransmitter
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Agonist
mimics neurotransmitter action. ex: Acetylcholine (agonist= nicotine)
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Antagonist
opposes action of a neurotransmitter. ex: acetylcholine (antagonist= curare)
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where do drugs have actions?
at neurotransmitter sites, some drugs will also bind at those receptor sites, act as a neurotransmitter (agonist), some will bind to the receptor site and oppose and prevent the action (antagonist)
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Acetylcholine
alerting neurotransmitter, activates motor neurons controlling skeletal muscles. attention, arousal, memory. decrease as we get older, it is thought that this is why we get slower and memories are worse
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Dopamine
pleasure transmitter, drugs that are abused usually related dopamine, voluntary movement , pleasurable emotions, decrease levels associated with parkinsons, overactivity at DA synapses associated with schiz
cocaine and amphetamines elevate activity at DA synapses
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Serotonin
linked to depression, drugs prevent uptake of natural serotonin, involved in sleep/ tired/ eating/ aggression.
abnormal levels may contribute to depression and OCD
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Norepinephrine
contributes to mood and arousal
| cocaine and amphetamines elevate activity
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What common neurotransmitters are linked to depression
norepinephrine, serotonin, dopamine
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Gaba
inhibitory transmitter, calming, 40% of synapses in our brain, dampen activity, decrease likely hood of action potential, linked to anxiety.
50
Glutamate
only exhibitory, different drugs that bind to these receptor sites, alleviation of symptoms for a few weeks
51
Endorphins
naturally occuring neurotransmitters that are associated with pain relief, pain drugs have actions as endorphins and bind effectively to these receptors sites and relieve pain better than our own body. Cannabis is linked to activity at these sites.
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Peripheral Nervous System (PNS)
NOT the brain or the spinal chord
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Somatic
voluntary part that allows us to make movements
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afferent
sensory neuro that bring info IN to the nervous system
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efferent
away from the nervous, OUT
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Autonomic
controls various activities automatically
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parasympathetic systems
returns body to resting state (rest and digest)
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sympathetic system
prepares body for action (fight or flight)
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Central Nervous System
central in terms of its essential for us to be alive
60
Meninges
multilayered sac a brain and the spinal chord
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Cerebrospinal Fluid (CSF)
removes waste from the brain and also cushioning of the brain
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Spinal Chord Damage
Paraplegic, quadriplegic. spinal chord can still have its own reflexes
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paraplegic
loss of movement and sensation in lower limbs, different degrees
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Quadriplegic
loss of movement and sensation in all four limbs
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Electrical Recording
applying electrode to the outside of the skull, apply gel to allow those record electro brain activity
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Electroencephalograph (EEG)
frequency of electrical brain activity, doesnt tell us specifically where the activity is coming from
67
Lesioning
destroy portion of brain to determine which behaviours are affected, damage to animal brains to figure out what is affected by the part of the brain. Stereotastic, we will damage this part of the brain and see what behaviour is affected. Can't make a lesion that is permanent to a human
68
Virtual Lesions
transcranial magnetic stimulation (TMS) take a magnetic coil that can disrupt or enhance that process of the brain and see what behaviours are impacted
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Electrical Stimulation of the Brain
surgeons will use an electrode, small pulse, stimulate that part of the brain to make sure if they are removing a part that they wont remove a part that has a crucial function
70
Computerized Tomography (CT)
takes x rays all around the head to give us a visualization of the brain, limited information given
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Positron Emission Tomography (PET)
allows us to examine blood flow/ metabolic activity in a functioning brain, gives us functional information as well as parts if the brain that are specially active, involves an injection of a substance that has a radioactive tracker, used commonly in terms of looking at certain structures
72
Magnetic Resonance Imaging (MRI) and functional MRI
uses a combination of magnetic fields and radio waves and computerized techniques to give us an image of the brain, shows info the blood flow in the brain $$
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The brain
composed of a variety of structures and each structure is related to a different types of processes
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brain stem
hindbrain, midbrain, diencephalon
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hindbrain
lowest part of the brain, highest part of the spinal chord,
| Medulla, pons, cerebellum, reticular formation,
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pons
bridge between the lowest order and higher order structures of the brain, sleep arousal
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reticular Formation
bond of fiber from lower order and stretches across the hindbrain: produces arousal in the brain and asleep
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Cerebellum
receives information from the sensory systems, fine motor movements
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Medulla
controls reflexes like sneezes and coughs, unconscious actions, breathing,
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Midbrain
integrates sensory process: allowed to orient information, owed to some of these processes -dopamine system
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dopamine System
in midbrain, voluntary movement
| substantia nigra: deteriorates in people with parkinson, less and less neurons being used and less dopamine being used
82
Diencephalon
Thalamus, hypothalamus
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thalamus
sensory waste system, all the info process will go to the thalamus which will then pass it on to other areas (rerouted), the only sense that doesn't go through directly is smell but will eventually reach
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hypothalamus
basically regulates biological needs, automatic nervous system, executes function that we are not aware of or in control of. also involved in endocrine system which releases hormones
85
Forebrain
largest and most complex: limbic system and cerebrum
| extremely large in humans
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Limbic System
seat of our motion, pleasure sensors, fear, motivation etc.
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hippocampus
in limbic system, key role in memory, implicated in formation of long lasting memories, remembering about where we are in space
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Amygdala
in limbic system, formation of fear responses, key in terms of expressing fear.
89
Cerebrum
responsible for complex thought, heavily folded outer layer; cerebral cortex Sulci, gyri
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Sulci
cracks in brain
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Gyri
bumps in brain
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two hemispheres
right and left, cracked appearence
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four lobes
frontal lobe, occipital, parietal, temporal
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Frontal Lobe
largest, motor movements, planning decision making, attend certain info, ignore others
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occipital lobe
involved in visual processes
96
Parietal Lobe
Where our body is in space, sensation of touch, somatosensory cortex (different sensory information from the body get processed in that cortex)
97
Temporal Lobe
Auditory cortex, our ability to use language and to communicate with speech is communicated to the left hemisphere
98
Corpus Callosum
band of 200 million fibers, extend from one hemisphere to the other, important to transfer information from one hemisphere to the other, to stop epilepsy from spreading they would cut the corpus callosum, tested in animals they could still perform tasks
99
Plasticity of the Brain
1) role of experience
2) reorganizing due to damage
3) neurogenesis in the hippocampus and the olfactory bulb
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plasticity
brain changes over time, reduced as we get older
101
changes in the brain
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some connections (synaptic) can be pruned, constantly changing (memories), experience results in change (ex. musicians)
produce new neuron connections when damage occurs in the body
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102
neurogenesis
New neurons being formed
103
plasticity of structures in the brain
hippocampus new neurons being formed, humans and animals, olfactory bulb in animals new neurons are being formed, no evidence for new neurons being formed elsewhere in the brain
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damage to pathways in the brain
not repairing damaged neurons but creating new connections and forming new neurons in the brain, reorganizing existing ones
105
Hemisphere control
left controls right, right controls left, one hemisphere can be removed if patient is young enough
106
Cerebral laterality
tendency for neuron functions or cognitive processes to be specialized to one side of the brain (ex: left side: wernickes and broca-- aphasia)
107
brocas area
speech production (if damaged, can understand speech but can't produce smooth (choppy, pauses))
108
Wernickes area
speech comprehension temporal (can produce speech but it doesnt make sense, produce language but it makes no sense)
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Aphasia
damage to both wernickes and brocas
110
split brain
severe corpus callosum due to epilepsy (removing a hemisphere)
111
split brain patients
right or left visual field, unable to identify in one but can in the other, left visual field is processed in right, right visual field is processed in left hemisphere, if we present the information is present to right it will be processed in the left and vice versa, depending on which visual field we present the information will determine how capable they are of identifying.
112
endocrine
glands secret chemicals into the blood stream, control bodily functioning, hormones. Brain communicate with the body through the endocrine system
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efficiency of endocrine
unlike action potential, hormone action happens over a longer timeframe and the hormones are distributed in various areas of the body
114
structure in the brain that controls endocrine
hypothalamus--> pituitary gland
115
Pituitary gland
master gland, will activate most hormones to places in the body that will secrete other hormones into the blood
116
hormones
have multiple functions, depending on where they are having their actions will depend what they do
117
Basic Principals of Genetics
chromosomes and DNA (23 pairs in humans)
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Genes
DNA segments that carry heredity info, except identical twins, everyone has a unique set of genes
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genetic information
codes for characteristics, blood type etc.
120
How does DNA relate to our behaviour
in terms of genetic info contained in chromosomes, DNA segments will contain sequence for protein
121
Adoption studies
look at how that person is similar to biological parents (genetics) vs how similar they are to their adoptive parents (environment)
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epigenetics
suggests that environment can have an impact on genetic expression in future generations, heritable changes to gene expression, passed from parents to their offspring that dont have anything to do with their DNA sequence. Parents choice in behaviour may have an affect on future generations
